Consumption of redox energy by glutathione metabolism contributes to hypoxia/ reoxygenation-induced injury in astrocytes
- First Online:
- 63 Downloads
The role of glutathione during ischemia/reperfusion is still a controversial issue. Glutathione should exert beneficial effects in the situation of ischemia/reperfusion due to its antioxidative potency. However, increasing survival time after transient ischemia and hypoxia has been reported for glutathione depleted cells. This work was aimed to analyse whether glutathione metabolism essentially contributes to redox energy failure and subsequent cell damage during ischemia/reperfusion. For this purpose, primary astrocyte rich cell cultures were subjected to 1 h hypoxia followed by up to 4 h reoxygenation in combination with substrate deprivation and glutathione depletion. The ability of the cells to reduce MTT was used to quantify the redox power of the cells. Inhibition of glutathione synthesis by L-buthionine-(S,R)-sulfoximine (BSO) caused depletion of cellular glutathione within 24 h and increase in MTT reduction by about 10% under normoxic conditions. Reoxygenation following 1 h of hypoxia was associated with decrease in MTT reduction which was enhanced by substrate deprivation. Glutathione depletion reduced hypoxia-induced decrease in MTT reduction. Three hours of substrate deprivation prior hypoxia resulted in lower levels of MTT reduction during reoxygenaton. Our data suggest that in situations of oxidative stress such as ischemia/reperfusion, glutathione metabolism may causes decrease of the cellular redox energy below a threshold level required for basic cellular functions finally resulting in cell injury.
Unable to display preview. Download preview PDF.
- 1.Merad-Saidoune M, Boitier E, Nicole A, Marsac C, Martinou JC, Sola B, Sinet PM, Ceballos-Picot I: Overproduction of Cu/Zn-superoxide dismutase or Bcl-2 prevents the brain mitochondrial respiratory dysfunction induced by glutathione depletion. Exp Neurol 158: 428–436, 1999PubMedCrossRefGoogle Scholar
- 13.Langeveld CH, Jongenelen CA, Schepens E, Stoof JC, Bast A, Drukarch B: Cultured rat striatal and cortical astrocytes protect mesencephalic dopaminergic neurons against hydrogen peroxide toxicity independent of their effect on neuronal development. Neurosci Lett 192: 13–16, 1995PubMedCrossRefGoogle Scholar
- 14.Makar TK, Nedergaard M, Preuss A, Gelbard AS, Perumal AS, Cooper AJ: Vitamin E, ascorbate, glutathione, glutathione disulfide, and enzymes of glutathione metabolism in cultures of chick astrocytes and neurons: evidence that astrocytes play an important role in antioxidative processes in the brain. J Neurochem 62: 45–53, 1994PubMedGoogle Scholar
- 28.Berridge MV, Tan AS: Characterization of the cellular reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT): subcellular localization, substrate dependence, and involvement of mitochondrial electron transport in MTT reduction. Arch Biochem Biophys 303: 474–482, 1993PubMedCrossRefGoogle Scholar